Drafting machine



Jan. 4, 1966 P. GRAHAM 3,226,829

DRAFTING MACHINE Filed Feb. 6, 1962 2 Sheets-Sheet 1 I7cl0 /////////A F|G.2 I 74 75 3 INVENTOR. Phillip Graham ka d ATTORNEY P. GRAHAM DRAFTING MACHINE Jan. 4, 1966 2 Sheets-Sheet 2 Filed Feb. 6, 1962 INVENTOR.

Phillip Graham 2/ A? AT.TORNEY mdE United States Patent 0 3,226,829 DRAFTING MACHINE Phillip Graham, 2825 Glenmcre Ave, Pittsburgh 16, Pa. Filed Feb. 6, 1962, Ser. No. 171,387 13 Claims. (Cl. 33-18) This invention relates to a drafting machine for en- I gineering drafting work and the like, and is a continuation-in-part of my copending applications: Serial No. 767,157, filed October 14, 1958, entitled Graphic Machine, now Patent No. 3,020,640, and Serial No. 806,963, filed April 16, 1959, entitled Graphic Machine, now Patent No. 3,120,060. Applicant also claims rights to earlier filing dates to common subject matters that are described in the present application, which were also described n his applications Serial No. 364,674, filed June 29, 1953, entitled Graphic Machine, now Patent No. 2,882,604; and Serial No. 221,005, filed April 14, 1951, entitled Graphic Machine, which has been abandoned. Application Serial No. 221,005 was a divisional application of application Serial No. 18,988, filed March 17, 1948, entitled Graphic Machine, now Patent No. 2,701,417. Therefore, application Serial No. 221,005 is entitled to the same filing date as application Serial No. 18,988. Application Serial No. 806,963 is a continuation-in-part of application Serial No. 364,674, and application Serial No. 767,157 is a continuation-in-part of application Serial No. 221,005. More particularly, it relates to a flexible drafting machine which enables a draftsman to speedily and accurately draw technical sketches on a drawing surface that is on the underside of a translucent or opaque drafting board. The drafting machine, briefly, has an automatic mechanism and a simple main control to allow the draftsman to draw accurate straight line sketches with substantially natural free-hand drawing movements. The machine also has the means to allow a draftsman to draw a cleaner and more likely, acceptable, complex patent drawing and the like with more speed, with less effort, less skill, and at a lower cost than with conventional equipment.

There is need for means to draw complex patent drawings, and the like, faster and at a lower cost than can be done with conventional means. The high cost of making complex patent drawings greatly discourages the general public from patenting new ideas.

Complex patent drawings are much more costly to draw than are common types of technical drawings having the equivalent sketches and requiring the equivalent amount of brain work. The higher cost of the patent drawings is caused by the need to neatly ink the drawings without smudging the lines and to keep the drawings clean, so the drawings can be reproduced without dirt or smudges also being reproduced. With conventional equipment, a patent draftsman must work slowly and carefully to avoid smearing inked lines, to avoid making ragged lines, because of lint catching on his pen or the ink running at scratched erasures, and to avoid making false lines that must be erased by scratching the work with a knife; also to avoid soiling the drawing with sweat and dirt. The draftsman spends considerable time in waiting for ink to dry. Much time is spent in scaling to proportion the sketch parts properly, and a great amount of time and effort is spent in moving straight edges, triangles,

and lettering guides into exacting positions for drawing.

The drafting machine of the present invention has means to eliminate the factors that cause complex patent drawings to be so costly and time consuming to make. The machine allows rapid and accurate uninterrupted drawing on the underside of a drawing board. The automatic mechanism allows the draftsman to accurately measure and draw selective width, dense, straight lines at right angles to each other, also to draw diagonal lines 3,22%,h29 i atented Jan. 4, 1966 and selective width lines for lettering, symbols, and the like.

The present invention is an improvement over the device described in my Patent No. 3,020,640, since it has means to allow a draftsman to accurately guide an inverted marking element that can be used to draw patent drawings and the like on the underside of a drawing board. The present invention eliminates the faults of the combination of the copending application that describes an inverted master carriage and inverted marker below a drawing board. The older combination did not have a practical means to accurately guide the inverted master carriage and inverted marker, particularly when drawing on almost opaque patent drawing paper. Although a combination shown in my copending application can be used to control an inverted marker with a master carriage above the drawing board, the present invention is simpler in construction, less cumbersome, requires fewer parts, weighs less, requires less effort to manipulate, and is less costly to manufacture. The present machine has a master carriage that can be used to make a finished patent drawing or the like above it by accurately guiding a control on the carriage over a preliminary, rough lined drawing that is below the carriage, thus eliminating the need for a second carriage, a second beam, chains and sprockets to interconnect two carriages.

The present invention has controls on a carriage below a drawing board that are responsive to natural drawing movements and mirror guiding means to enable a draftsman to accurately control an inverted marker when drawing on an inverted opaque patent drawing and the like.

The present invention has an improved index arm that is simpler to make and operate. The improved index arm is like the index arm described in my Patent No. 3,120,060.

An object of the present invention is to provide a novel drafting machine for engineering drafting and the like, including automatic features below a drawing board, that allows the draftsman to rapidly, accurately, and neatly draw and scale sketch lines on at least the underside of a drawing board, the automatic features being responsive to substantially free-hand normal drawing movements that are made below the drawing surface. Furthermore, the automatic features include control means that are pivoted for preselecting the path of movement of a marker to draw a line along a straight path, or a line along a straight path at ninety degrees to the first path.

Another object is to provide a novel automatic drafting machine for engineering drafting, including a carriage having a marker on its lower extremity and another on its upper extremity to allow a draftsman to simultaneously trace and/or draw two sketches that are reverse of each other, the automatic features being responsive to substantially free-hand normal drawing movements, to accurately draw and scale straight lines ninety-degrees to each other.

A still further object of my invention is to provide a novel automatic drafting machine for engineering drafting, having two interconnected carriages below a drawing board for tracing and/or drawing two sketches, at least one of the sketches being drawn on the underside of the board, the automatic features being responsive .to substantially free-hand drawing movements that are made below the plane of the underside of the board.

A still further object or" my invention is to provide a drafting machine which, though made up of a plurality of parts, is neverethless exceedingly simple in operation and may be readily operated by semi-skilled labor, frail, or physically handicapped persons, such as one armed persons.

Other objects and advantages of my invention will become apparent from a study of the following description taken with the accompanying drawings wherein:

FIG. 1 is a plan view showing an automatic drafting machine embodying the principles of my invention;

FIG. 2 is a sectional elevational view taken along line 2-2 of FIG. 1;

FIG. 3 is a fragmentary elevational view showing a portion of a secondary carriage;

FIG. 4 is a sectional elevational view taken substantially diagonally through a master carriage;

FIG. 5 is a fragmentary elevational view showing a modification that has a pen-type marker which is retractable.

FIG. 1 is a plan view of a flexible drafting machine which illustrates the principles of my invention. The machine consists of an upper drawing board 1. A board 1 may be made of transparent or translucent materials for use in a wide range of work, as it would act both as a drawing board and as a guiding means to allow the draftsman to scan the drawing surface from above, so as to view additional guiding means below the board that indicates the vertical axis of the marker. An opaque board may be used when there is no need to see through the board. A translucent board 1 may be made of a sheet of plate glass to obtain a flat, smooth, hard and durable surface. The board 1 is skewed laterally to allow the draftsman to easily reach and manipulate the drafting machine controls. The board 1 is mounted on four supports or legs 2. The legs 2 are mounted on the lower board or base 3. The lower board 3 may be a table top. The board 3 may be made of a fiat panel of steel, glass, wood or plastic. The board 3 or a portion of it may be a mirror so the drawing surface on the underside of board 1 can be seen readily from a high viewpoint, that is, laterally away from the mirror. Such a mirrored board 3 would act as a guiding means to enable the draftsman to view sketching work and to aim the marking means. The legs 2 may be rigidly fastened to the board 3. The tops of the legs 2 may be tapered to fit tapered holes in the board 1. The tapered fittings allow the board 1 to be removed and to be repositioned accurately. Boards 1 and 3 are mounted parallel to each other.

A track or frame 4 engages the top surface of the lower board 3. A beam G is mounted for reciprocable movement on the track 4. A master or main carriage M is mounted for reciprocable movement on the beam G. A secondary carriage BR may also be mounted on the beam G and be interconnected with the carriage M so as to be responsive to controls on carriage M. The marking means are mounted on the carriages. The carriage BR may be selectively coupled to carriage M, so as to cause it to move in the same or opposite directions, thus allowing identical sketching or the making of sketches that are the opposite of each other. A fixed straight edge 5 is fastened securely to the top surface of board 3. The frame 4 may be positioned against the edge 5 so as to draw horizontal and vertical lines. The

pins on and 6b bear against the edge 5. The frame 4 may be selectively tilted laterally with respect to the edge 5 by selectively adjusting the pin 60 laterally on the index arm N and engaging it and pin 6a or 6b against the edge 5. Protractor clamps C1, C2, and C3 may be used to selectively clamp the pins 6a, 6b, and 6c to the edge 5.

The index arm N may be removed and be attached to the position N1 on the adjacent side of the frame 4. This shifting of the index arm allows the frame 4 to be rotated ninety degrees with respect to straight edge 5.

Except for improvements, the frame 4, beam G, carriages M and ER, index arm N, pins 651, 6b, and 6c and protractor clamps C1, C2, and C3, and a fixed straight edge 5 are described in detail in my Patent No. 3,020,640. My Patent No. 2,882,604 describes the pins, clamps and index arm more thoroughly. My Patent No. 3,120,060 describes an improved index arm.

A slidable straight edge 7 engages the frame 4 and it is movable to allow it to be positioned so as to align auxiliary guides including lettering guides with the beam G. The straight edge 7 may be used to position the tiltable L-shaped square Q. The square Q is needed to guide the carriage M when using both carriages simultaneously to draw two opposite diagonal lines that are diagonal with respect to the beam G. The straight edge 7 and the square Q may be removed when they are not being used to provide unobstructed space for the draftsmans arm movements.

The beam G may be kept in true alignment with the frame 4 by attaching it to the shaft 8. The shaft 8 has a gear keyed to each end to engage a pair of racks on the frame. A modification may have a member (not shown) that acts as both a beam and a shaft, as described in my Patent No. 3,020,640.

As shown in FIG. 4, carriage M has an inverted air brush marker D1 to draw lines on the Bristol board type of patent drawing paper 9 which is used for finished patent drawings. The patent paper 9 is attached to the lower surface of the upper board 1. The carriage M has an air brush marker D2 to draw on a piece of drafting film 10 or the like, which is attached to the upper surface of the lower board 3. As shown in FIG. 3, carriage BR has an inverted air brush marker D3 to draw lines on paper 9 or the lower surface of the upper board 1 and an air brush marker D4 to draw lines on the film 10 or the upper surface of the lower board 3. The marker D4 may be used as a guiding or tracing means to follow a preliminary sketch on film 10 when making a finished paper patent drawing 9. All the air brushes are responsive to movements of the control arm E on carriage M. The arm E is selectively pivoted to select the widths of lines to be drawn and to select the path in which to draw a straight line and be pivoted differently to select the widths of lines to be drawn and to select a path at right angles to the other path. The arm E is depressed to cause the air brushes to start to mark, and the arm E is lifted to stop the drawing action. The auxiliary control or handle Y may be gripped like a pencil is gripped, and be rotated to an extent to pivot the arm E. The control Y is depressed to depress the arm E. Any of the air brushes can be used alone or with one or more of the other air brushes. The other air brushes can be inactivated by controls in control panel K. The carriage M may have tracers or guides to allow the draftsman to trace over a drawing, so as to guide an interconnected remote marker. The improvements in the carriage M include having an offset 11, which supports the frame 12. The frame 12 supports the air brush D1 and the crossed hairs unit 13. The unit 13 is a guide means or orienting means to allow the draftsman to guide or aim a marker. The light beam 19 projects the image of the crossed hairs unit 13 onto the drawing surface to indicate the exact center of the marker when the marker is retracted or inactivated. A rigid tube 14 is keyed to the arm E. The tube 14 has a rectangular hole to fit the plunger 15. An offset on tube 14 engages and depresses the plunger or the control cable 16 when the arm E is lowered. The control cable 16 turns on the air brush D1 when its plunger is depressed, and the air brush is shut off when the arm E is raised. The control cable 16 is similar to a common camera cable release. The diaphragm disk 17 pivots to align a selective diaphragm to the air brush D1. The diaphragm disk 17 may be removed and be replaced with a different type disk having openings with different diameters.

The improved carriage M may have a means to divert the projected scale image to the surface of board 1 for use when the draftsman watches the sketching surface through the board 1 or watches the surface reflections through a mirror type of board 3. The prism 18 can be pivoted downwardly forty-five degrees to allow the light beam 19 from the electric light bulb 20 to carry the scale image from scale 21 to the tilted mirror 22. The mirror 22 reflects the light beam 19 past the gear 23 to the tilted mirror 24. The light beam 19 reflects from mirror 24 to mirror 25, then it is reflected to the lower surface of board 1 or the surface of drawing 9. The hub 26 is transparent to allow the light beam 19 to pass through it. The hub 26 supports the disk 17.

When the sketching action is to be viewed on board 3 or film 10, the prism 18 is pivoted to the position shown so it bends the light beam 19 downwardly to prism 27. Prism 27 bends the light beam 1? towards prism 28 and prism 28 bends it to direct it through the crossed hairs unit 13:: and the transparent hub 25a onto the lower drawing surface. The hub 25a supports a diaphragm disk 17a which is like disk 17. i The tube 14a is similar to tube 14 and the sliding plunger 15:: is similar to plunger 15. The control cable 16a is similar to cable 16.

The improvements in the carriage BR are similar to i the improvements for mounting an inverted air brush in carriage M. As shown in FIG; 3, the frame of the carriage BR has an offset 29 which supports a frame 12a. Frame 12a is similar to frame 12. Frame 12a supports the air brush D3. The rigid tube 14!) is similar to tube 14. The plunger 15b is similar to plunger 15. The control cable 161) is similar to cable 16. The diaphragm disk 17b is similar to disk 17. The hub 26b supports the disk 26. The tubes 14b and 14c are mounted on the pivot arm F. The arm F pivots because it is keyed to pivot chain 30. The arm F reciprocates vertically when magnets 31 are activated. The movements of arm F are responsive to movements of control arm E. The tube 140 is similar to tube 14a. The plunger 150 is similar to plunger 15a. Control cable Inc is similar to cable 16a. The diaphragm disk 170 is similar to disk 17a and the hub 260 is similar to the hub 2601.

FIG. 5 illustrates a modification having a means of mounting an inverted ruling pen marker P or the like that must be moved against the drawing surface on board 1 to cause marking, and be retracted to terminate the marking action. The pen P has a long contact edge for making selective width lines. The pen P may be wick-fed from the ink reservoir 32. The pen is described in my Patent No. 3,020,640. The pen blades can also be used to score lines by using carbon paper backing of transparent drawing paper, with the carbon touching the drawing paper. The blades of the pen P press against the surface of the drawingpaper to cause the carbonto mark lines on the drawing paper, the pen P being pivoted by pivoting arm E to make selective width lines.

The pen P has a plunger 15d which is similar to plunger 15. The plunger 15d slides in tube Md. The tube Mn? is similar to the tube 14. A support33 is attached to the offset 11. The support 33 has a thin resilient upper portion 33a which supports a unit having a pair of magnets 34. A disk-shaped offset 35 of pen P is made of iron so it will attract the pair of magnets 34 when they are activated. The magnets 34 are activated in response to movements of control arm E. The magnets 34 raise the pen P so the pen blades bear, against the drawing surface on the underside of board 1. When the arm E is raised, the magnets 34- are deactivated and the resiliency of the portion 33a forces the pen P to retract downwardly, overcoming the friction between the plunger 15d and the tube Md. The support tip 33b acts as a limit stop to prevent the pen P from moving downwardly too far.

A- crossed hairs unit 13 is supported by an offset on the support 33.

Other markers that can be mountedsimilar to pen P include double pen markers and pencil-type markers, which are described in my Patent No. 3,020,640. A double pen may have different colors on each of the two portions, also each of the pens may be set to give different width lines. The double pen may act as four scoring markers.

The improvements described for making a better drafting machine can be more readily understood by making a thorough study of the many drawings and the specification of my Patent No. 3,020,640. The patent describes in great detail the intricate mechanism that constitutes the major portion of the present drafting machine, which does not differ from the major portion of the mechanism of the machine described in my Patent No. 3,020,640. The following brief description of some of the mechanism shown in the present application will enable those studying the present specification to understand the principles involved, even before studying my Patent No. 3,020,640.

An endless chain 36 may be mounted on the beam G to selectively couple carriage M to carriage BR. Fragments of chain 36 are shown in position in FIG. 4. Switching means on the carriages allow selectively coupling to the portions of chain 36 on either side of the center of the beam G, so as to cause carriage BR to move in the same direction or the opposite direction of lateral movements of carriage M. The switching means also allows the carriage M to be uncoupled from the chain 36 when the carriage M is to be used alone.

As shown in FIG. 4, carriage M has a main vertical frame part 37 to which an upper frame part 38 and a lower frame part 39 are attached. The offset 11 is attached to the upper portion of frame part 33. A frame part 40 is attached to the frame part 37 and coacts with it to pivotally support a sprocket 41. The sprocket 41 has a square hole to slidably engage square portion of a vertical shaft 42 and to position the shaft. The upper end of shaft 32 engages a bearing 43. The bearing 43 is threaded into the control arm frame 44. The lower end of frame 44 is ecurely keyed to the bearing 45. The lower end of the shaft 42 rotates in bearing 45. A thin round. shaft 46 is fixed to frame 37. The upper portion of shaft 46 slidably engages a hole in the bearing 45 and the shaft 42 to center the bearing 45 and the shaft 42.

The shaft 42 and the control arm E can be lowered to start drawing action and be raised to stop the drawing action. The auxiliary control Y or the frame 44 of arm B may be gripped and be forced down to start drawing action. After drawing a line, the operator releases the downward pressure, thereby allowing the spring 47, which bears against a wide portion of the shaft 42, to pressure the shaft 42 upwardly and thus raise the arm E.

When the arm E is depressed or lowered, the downward movement activates the air-brush markers D1 and D2 by depressing the cable releases 16 and 16a, which open the valves of the air brushes to cause the marking fluid to spray to form inked lines. The downward control movement of the arm E also rocks the rocker parts 48, 49, and 50, which locks the directional locking means on the carriage M so as to lock the beam G so it cannot move, while allowing the carriage M to move along the beam G, or by locking the carriage M so it cannot move along the beam G, while allowing the beam G to move along the track 4. Furthermore, the downward control movement of arm E moves and depresses fingers on the jack R to cause the magnets 31 on carriage BR to depress the arm F and thus the cable releases 16b and Ida to cause the valves on the air-brush markers D3 and D4 to open to cause ink to spray to form ink lines. This depressing of the fingers of the jack R also may be used to cause selective powered movement of the carriage M along the beam G or the movement of the beam G along the track 4. The downward control movement of arm E lowers the dotting cam means I so any one of its three cam-like portions can be selectively engaged by the adjustable cam follower control 51 to make various types of intermittent lines. There is play between bearing :3 and rocker part 48 that allows the arm E to be raised slightly after it is lowered without unlocking the directional locking means, thus allowing a dotted line to be drawn. A slight downward movement of the arm E may also cause the rocker part 49 to move a jack on the powered vertical movement unit V to cause magnets on unit V to power move the arm E fully downwardly. A limited manual lifting action of the arm E may be made to cause the unit V to power lift the arm E fully to unlock it.

Before the arm E is lowered to lock the machine for a selective operation, it is selectively pivoted laterally to selective zones to pre-select the operation to be made, including directional movement and power movement of the marking means along a straight path or another path ninety degrees to the first path, in addition to pre-selecting a line of selective width or otherwise contrasting to be drawn. The arm E can be more readily pivoted laterally and then be lowered by manipulating the handle Y. A beveled gear 52, which is keyed to the shaft 53 of handle Y meshes with a beveled gear 54 that is keyed to the bearing 45. The handle Y is gripped like a pencil is gripped, then the operator rotates or pivots the handle Y by rolling it between his thumb and index finger to cause the gears to rotate and the arm E to pivot laterally. The pivoting of control E causes the sprocket 5'5 to move the endless chain 56. The movement of the chain 56 causes the sprocket 57 and the zone cam 58 to pivot. The sprocket 57 is keyed to the cam 53. The cam 58 has zone slots to form the zones. When the arm E is lowered, the conical tip 50a on the rocker part 50 engages one of the zone slots. The centers of the zone slots are offset either inwardly or outwardly from the concentric center line of the cam 58. The concentric center line is aligned with the center of the tip 50a when the tip is raised. The spring 50!) tends to keep the tip 50a raised. When the arm E is lowered, it forces the rocker parts 43 and 49 to rock to cause the rocker 50 to rock vertically. This action also causes the rocker 50 to pivot laterally slightly to allow the tip 50a to penetrate a zone slot. The slight lateral pivoting of the rocker part 50 causes the support 59, vertical shaft 60, and rocker 61 to pivot laterally slightly. The rocker 61 is keyed to the bottom of the shaft 60. The rocker 61 has two arms that simultaneously act when the rocker 61 pivots to selectively lock or clutch a geared clutch unit and to unlock another geared clutch unit the cause the carriage M to lock so it cannot move along beam G, while allowing beam G to move laterally, or to cause the beam G to lock so it cannot move while allowing carriage M to move along the beam G. Each of the geared clutch units has a double clutch that performs two operations when it shifts in response to a movement of the rocker 61. The whole rocker 61 and the geared clutches are shown in detail and fully described in my Patent No. 3,020,640.

When the directional locking mechanism is selectively controlled so it locks the beam G so it cannot move, the carriage M can be moved laterally along the beam G. This operation is allowed because a spur gear that is mounted on the carriage engages the rack-like top portion 62 of the beam G. Manual or powered lateral movement of the carriage M causes the spur gear to rotate. One of the clutch units interconnects the spur gear and the beveled gear 23. The gear 23 is keyed to the vertical shaft 63. When the directional locking mechanism is selectively controlled so it locks the carriage M so it cannot move along the beam G, the beam G and the square shaft S, shown in FIG. 1, can move along the track 4. The square shaft 8 is coupled to carriage M so the directional locking and driving mechanisms on the carriage M can lock or restrain the shaft 8 from rotating, thus preventing the beam G from moving or causing the shaft 8 to rotate to move the beam G. A second spur gear on the carriage M has a square hole which slidably engages the square shaft 8. The other geared clutch unit has a double clutch that simultaneously shifts with the other geared clutch unit in response to the movement of rocker 61, and couples the second spur gear to the beveled gear 64. The gear 64 is keyed to the vertical shaft 63. Each double clutch on each geared clutch unit works when the mechanism locks. When the rocker 61 shifts these clutches, one clutch of each double clutch unit causes coupling of gear means to allow selective movement, while the other clutch of each of the clutch units uncouples and locks the gear means to prevent movement in directions at right angles to the first movement. Therefore, the selective coupling of the directional locking mechanism in carriage M allows geared relationship between the carriage M and rack 62 on the top of beam G and to the square shaft 8.

The carriage M, being in selective geared relationship with the beam G and the shaft 8, and thus the track 4, allows the carriage M and the beam G to be moved with power means that is coupled to the shaft 63. The beveled gear 65 is engaged to the beveled gear 66. A motor is attached to the gear 66.

The machine may be used to draw selective width or contrast curved lines and the like to form free-hand and template guided letters, numerals, symbols, circles and the like. Such usage requires that the directional locking means be unlocked or be deactivated by loosening the machine screw 61a. The screw 61a acts as a control means to key the rocker 61 to the shaft 60, or to quickly deactivate the keying means.

An endless chain 67 may be mounted adjacent to chain 36 to allow the arm F on carriage BR to be selectively pivoted laterally in response to lateral pivoting of arm E to selectively vary the width of line to be drawn with the markers on carriage BR. A sprocket as is fastened, such as by welding, to the control arm frame 44. An endless chain 69 couples sprocket 68 to sprocket 70. A clutch 71 couples the chain 69 to the chain 67, therefore when the arm E is pivoted, the chain 67 is moved to cause the same or opposite movement to the arm F on carriage BR. The chain 30 on carriage BR is mounted like chain 69. The pivoting of arms E and F to vary the width of line or contrast to be drawn is the means to make various types of markers make selective width lines or other types of lines of selective contrast, including lines of selective color. Various types of such markers are described in my Patent No. 3,020,640, including light beam markers with various colors of filters on each marker to make selective colored lines of contrast on colored photographic film and the like. The colors are preselected by the extent of pivoting. The diaphragm disks 17, 17a, 17b, and 17c of the air brush markers D1, D2, D3, and D4 are pivoted laterally with gear 72 and 73 to bring selective sized diaphragrns into register with the air brush nozzles 74 to make selective width lines. Gears 72 are fastened to the plungers 15, 15a, 15b, and 15c. Gears 72 engage gears 73. Gears 73 are keyed to square shaft means 75. The diaphragm disks 1'7, 17a, 17b and 17c are keyed to the shaft means 75.

The markers D3 and D4 on carriage BR are automatically activated and deactivated in response to the vertical control movements that are made by arm E. Arm E is interconnected with electric wires to arm F on carriage BR. The wires carry electric current which is controlled by the jack R to cause the magnets 31 to attract the iron plate 76. The plate 76 is attached to the arm F, thus the arm F is pulled downwardly by magnets 31 to activate the markers D3 and D4. When the arm E is raised, the jack R breaks the circuit to the magnets 31 and allows the spring 77 to raise the arm F to deactivate the markers. The markers D3 and D4 can be made non-operative by making them non-responsive to movements of arm E by breaking the electric circuits with auxiliary controls in control panel K.

The vertical shaft 63 that interconnects the means to lock and drive the carriage M and the beam G, also acts to drive other parts of the carriage. Any rotation of shaft 63 causes rotation of a gear train formed by gears 78, 79, 79a, and 80 to drive a recording scale 21 to register the length of a line as it is drawn. The bottom of the gear 84) and the top of the scale 21 are clutched together to start scaling action by the pressure of the spring 81 when the arm E is lowered. The top of the gear 80 is coupled to the scale arm part 82. The arm part 82 is connected to arm part 83. The arm part 83 bears against the top of the dotting cam J to keep the slidable gear 80 raised and thus the scale 21 declutched until the arm E is lowered. The adjusting screw 84 is turned to selectively move the frame 85 which supports the lens 86, bulb 20, and other optical, parts to project a selective scale band onto the drawing surface. A spring 87 tends to force the frame 85 upwardly.

Any rotation of the shaft 63 also causes the rotation of sprockets 41 and 88. The endless chain 89 couples the sprockets to cause the, shaft 42 to rotate. The shaft 42 is rotated to rotate the dotting cam I. The rotation of the shaft 42 provides a means to rotate a tilted pencillike marker as described in Patent No. 3,620,640.

Other parts of the carriage M, shown in FIG. 4-, are an auxiliary reversing switch 90. Also, a hold-down part 91, which may be pulled outwardly to an extent to engage the top of the offset 92 to keep the arm E depressed and thus locked without manual effort while drawing a long line.

The present drafting machinecan be used to draw a simple patent drawing and the like faster and better than can be done with conventional equipment.

' The control Y is gripped and manipulated so as to draw, the marker D1 drawing on the paper 9 and the marker D2 drawing on the film 10.

The draftsman would draw the sketch on film that is opposite or reverse of the sketch required on the finished drawing 9, because the upper sketching action is the reverse of the lower sketching action. Perforated lettering guides may be placed upside down on the film 10* to obtain the proper lettering for the finished drawing 9.

The large gap or space between boards 1 and 3 allows the draftsman to see under the board 1 and the drawing on board 3, particularly so because patent drawings and many other types of technical drawings are small. The whole drafting machine may be tilted to allow the draftsman to more readily see thedrawing on board 3. When the board 3 or a portion of board 3 is a mirror, it allows the draftsman to occasionaliy observe the reflection of the paper 9 to see if the marker D1 is working properly. The draftsman concentrates on viewing the sketching lines on the film it) which is clearly within his field of vision to allow him to draw accurately. If the film 10 becomes soiled from the draftsmans hand or from splashed and smudged ink, no harm is donebecause the film 10 is discarded after the finished paper drawing 9 is finished. If preferred, a dry marker, such as a pencil-type marker (not shown), may be used instead of marker D2 to reduce the extent of smearing of lines. Pencil lines flake and smear slightly when rubbed by the draftsmans hand. Such a pencil marker is described in my Patent No. 3,020,640.

When a mirror is used for board 3, or a mirror is positioned on board 3, the film it may be omitted and the marker D2 may be shut off or be omitted. The draftsman could scan the mirrored reflection of the sketching, scaling image, and crossed hairs centering image on the paper 9. r

The drawing paper 9is kept perfectly clean and free of smeared lines while it is being drawn. Even on damp cool days when ink drys slowly, the draftsman can work speedily and continuously without the danger of smearing the ink, dirt, or sweat on paper 9 and ruining the work alreading done. Smeared ink lines on the Bristol board type of paper 9 are extremely difficult to erase without damaging the surface of the paper. When the paper surface is damaged, inked lines made later on the damaged surface tend to be ragged and quite often require that the drawing be discarded. Even soft erasers that are used to remove dirt from patent drawings and the like remove some of the ink and tend to make the lines slightly ragged.

The shielding of the paper 9 eliminates many troublesome factors that cause delays in drawing and cause poor drawings to be made. These problems of conventional drafting include falling dust and lint clogging pens and causing ragged lines to be made. Sweat and soil from the draftsmans hand cannot reach the paper 9. Drippage from the air brush D1 falls away from the drawing rather than onto the finished drawing. Lubricating oil from the drafting machine cannot reach the paper 9. An excessive spurt of ink from the air brush splashes down from the paper 9, thus not falling back on a large area as would be the action with conventional drafting means.

Since the paper 9 is so difficult to correct, drafting film may be used as an intermediate drawing instead of drawing directly on Bristol board. Revisions and corrections can be made on the film without damaging its surface. The sketching on film can be copied photographically to make a photo-lithograph, or the like, to provide a finished acceptable patent drawing. Sketching on drafting fiim allows reversing in processing, thus allowing the lower sketch on film 10 to be drawn without reversing it.

Extremely complex patent drawings can be drawn in preliminary form with the marker D2, then after corrections and revisions have been made, the drawing can be traced with the marker D2 acting as a guide means while the marker D1 can draw a finished drawing.

The marker D1 may sketch directly on the lower surface of the board 1, thus eliminating the sheet of drawing paper 9. When the board 1 is made of glass, at more trouble-free drawing surface is had because glass has a low coefficient of expansion from thermal changes and it is not affected by moisture changes. Conventional translucent plastic sprays can be used to size glass so ink and pencil lines can adhere to it. Drawing paper 9 absorbs moisture from the air and buckles, it also buckles from the moist ink. Both paper and film expand and contract considerably from temperature fluctuations. The board 1 can be removed for copying the drawing on it by photographing it, or for copying it by contact printing. The top surface of board 3 can be used as a sketching surface, the film ltl being eliminated. Cleaning solvents can be used to remove ink sketches from glass boards so the glass can be reused.

Sketching on lower board 3 or film it} can be eliminated 7 when drawing on a translucent board 1 or on translucent film attached to the underside of board 1. The draftsman can view the sketch lines, crossed-hairs centering image and the scale image through the translucent board l. A translucent board would not have shadows from straight edges and the like.

When the sketches to be drawn on a patent drawing or the like are largely symmetrical or repetitious, the draftsman may use the carriage BR along with the carriage M to draw opposite or identical sketch portions in response to movements of carriage M and its controls. The draftsman may also use thecarriage BR to wholely draw a sketch below the board 1 in response to drawing or tracing a sketch with the marker D2 on carriage M, thus the upper sketch would not obscure the sketch below when viewed from above through a translucent board or where a portion of the board is omitted (not shown).

The carriage M may be used as a remote control with the marker D3 on carriage BR drawing the finished drawings, such as a patent drawing. The interconnection between the carriages can be switched so that carriage BR moves oppositely from carriage M, thus the finished drawing would be identical (not reversed) to a preliminary drawing placed below M or a preliminary drawing used as a reference guide when it is not traced. This means would allow a thick patent drawing to be made without need to make a transparency and a lithograph.

When making a drawing with lines of two colors, marker D1 could have a different color from that of marker D3. All the markers may be set for making different width or different color lines or both different width and different colors.

A multi-colored drawing may be made by guiding or tracing the marker D2 over the lines of a preliminary drawing, each of the markers D1, D3, and D4 marking piews of transparent drafting film with a different color ink. The control K would be used to turn on the marker needed to obtain a given color and to turn off the others. The three pieces of drafting film could be removed and be superimposed, so the drawing could be photographically copied in color.

A modification may be made which would omit the markers D1 and D4. Such a combination would be useful in general to trace a preliminary drawing with marker D2 while marker D3 sketches the finished drawing.

When only a small low cost machine is required for making small unsymmetrical drawings, such as patent drawings, the carriage BR may be omitted.

While I have illustrated and described certain specific embodiments of my invention, it will be understood that these are by way of illustration only and that various changes and modifications will be readily suggested to those skilled in the art after having had the benefit of the present specification, but which are within the contemplation of the present invention and within the scope of the claims.

I claim:

1. A drafting machine comprising an upper drawing board mounted on support means and having a drawing surface on the underside thereof, a track mounted below said upper drawing board on a second drawing board spaced from said upper drawing board, a beam mounted for translating movement along said track to sweep under at least a portion of said upper drawing board, the longitudinal axis of said beam being perpendicular to the longitudinal axis of said track and parallel to the said drawing surface on said upper drawing board, a carriage means mounted on said beam for longitudinal reciprocable movement on said beam, and inverted marking element mounted on an upper portion of said carriage means adjacent to said drawing surface on the underside of said upper drawing board, control means mounted on said carriage means, a lower marking element attached to a second portion of said carriage means adjacent to said lower drawing board, said lower marking element and said inverted marking element being responsive to movements of said control means for marking said second and upper drawing boards, respectively, said control means including an arm pivoted on said carriage means, locking means responsive to the extent of pivoting movement of said arm for selectively locking said carriage means to said beam and allowing free translation movement of said beam or allowing free reciprocable movement of said carriage means on said beam and locking said beam to said track so as to selec tively draw lines along a straight path or another straight path at right angles thereto, whereby a draftsman can simultaneously draw two sketches rapidly with ease while keeping the drawing on said upper drawing board clean and unsmudged.

2. A machine as recited in claim 1 together with means, associated with at least said inverted marking element, responsive to said extent of pivoting movement of said arm to effect the drawing of lines which contrast with each other, whereby a fine and clean drawing can be made with case on at least said drawing surface on said upper drawing board.

3. A machine as recited in claim 1 together with means, associated with at least said inverted marking element, responsive to the said extent of pivoting movement of 12 said arm to effect the drawing of lines of selective width on at least said upper drawing board, whereby a fine and clean delineation can be made with ease on at least said drawing surface on said upper drawing board.

4. A machine as recited in claim 3 wherein at least said inverted marking element is an ink dispensing marker, whereby a fine inked drawing can be made on at least said upper drawing board, rapidly without being soiled with drippings and without delays to allow ink to dry.

5. A machine as recited in claim 3 wherein at least said inverted marking is an air brush, W1 ereby a fine inked drawing can be made on at least said upper drawing board, rapidly, without being smeared or being soiled with drippings and without said lines being made irregularly by foreign particles from said drawing surface.

6. A machine as recited in claim 3 together with means to automatically draw intermittent lines in response to another movement of said control means, whereby fine uniform intermittent lines can be drawn rapidly with ease.

'7. A machine as recited in claim 3 together with scale means mounted on said carriage means, means for zero setting said scale means in response to movement of said control means, said scale means including means to measure the length of a line as it is drawn, whereby fine accurateiy proportioned sketches can be drawn rapidly without interruptions for scaling.

8. A machine as recited in claim 3 together with means for unlocking said locking means to permit drawing curved lines and lettering lines of selective width, whereby all of the sketch lines on at least said upper drawing board can be made neatly and rapidly.

9. A machine as recited in claim 3 together with a straight edge, said track being tiltably mounted with respect to said straight edge selectively about two bearing points spaced along one side of said track, only one of said bearing points engaging said straight edge when the said track is tilted, said track having an indexing arm means attached to said track, the longitudinal center of said index arm means being parallel to said drawing surface and at right angles to said side of said track, said indexing arm means being positioned equidistantly between said bearing points, said indexing arm means including a pin equidistantly spaced from said bearing points, said pin being engageable with said straight edge and being adjustable to vary the distance between said track and said straight edge for selectively tilting the said track relative to the said straight edge, said track being tiltable in opposite directions by seiectively engaging the said bearing points and said pin against said straight edge to obtain opposite sets of sloping positions for the said track to allow the drawing of sets of lines ninety degrees to each other and oppositely sloped.

10. A machine as recited in claim 3 wherein said carriage means is a single carriage, whereby said machine is compact and useful to rapidly draw two sketches simultaneously and to maintain at least one sketch clean so it can be used to make a fine reproduction.

11. A machine as recited in claim 3 wherein said inverted marking element is laterally offset from said con trol means, whereby the space adjacent said control means is free of falling residue from said inverted marking element, allowing the control hand of said draftsman to remain clean.

12. A machine as recited in claim 3 wherein said carriage means includes a master carriage and a second carriage, and wherein said lower marking element and at least a major portion of said control means are mounted on said master carriage, and wherein said inverted marking element is mounted on said second carriage, coupling means for coupling said second carriage to said master carriage, said coupling means includes switching means for selectively coupling said carriages so that they will move in the same or in opposite directions to each other, whereby the sketching action on said upper drawing board can be made the same or the reverse of drawing movements made by said draftsman. I

13. A machine as recited in claim 10 together with means for unlocking said locking means to permitdrawing curved lines and lettering lines of selective width.

14. A machine as recited in claim 10 together with means to automatically draw intermittent lines in response to another movement of said control means.

15. A machine as recited in claim 10 together with scale means mounted on said single carriage, means for zero setting said scale means in response to movement of said control means, said scale means including means i to measure the length of a line as it is drawn.

16. A machine as recited in claim 13 together with means to automatically draw intermittent lines in response to another movement of said control means.

17. A machine as recited in claim 13 together with scale means mounted on said single carriage, means for zero setting said scale means in response to movement of 14 said control means, said scale means including means to measure the length of a line as it is drawn.

18. A machine as recited in claim 17 together with means to project a luminous centering image on one of said drawing boards in alignment with the longitudinal axis of one of said marking elements, whereby said one of said marking elements can be aligned with a predetermined point on said one of said drawing boards, allowing said draftsman to draw from a position that is nearly an arms length distance from said machine.

References Cited by the Examiner UNITED STATES PATENTS 1,059,893 4/1913 Milde 3324 1,831,390 11/1931 Lindelov 33--24 X 3,020,640 2/ 1962 Graham 33--23 ISAAC LISANN, Primary Examiner.

ROBERT L. EVANS, Examiner. 

1. A DRAFTING MACHINE COMPRISING AN UPPER DRAWING BOARD MOUNTED ON SUPPORT MEANS AND HAVING A DRAWING SURFACE ON THE UNDERSIDE THEREOF, A TRACK MOUNTED BELOW SAID UPPER DRAWING BOARD ON A SECOND DRAWING BOARD SPACED FROM SAID UPPER DRAWING BOARD, A BEAM MOUNTED FOR TRANSLATING MOVEMENT ALONG SAID TRACK TO SWEEP UNDER AT LEAST A PORTION OF SAID UPPER DRAWING BOARD, THE LONGITUDINAL AXIS OF SAID BEAM BEING PERPENDICULAR TO THE LONGITUDINAL AXIS OF SAID TRACK AND PARALLEL TO THE SAID DRAWING SURFACE ON SAID UPPER DRAWING BOARD, A CARRIAGE MEANS MOUNTED ON SAID BEAM FOR LONGITUDINAL RECIPROCABLE MOVEMENT ON SAID BEAM, AND INVERTED MARKING ELEMENT MOUNTED ON A UPPER PORTION OF SAID CARRIAGE MEANS ADJACENT TO SAID DRAWING SURFACE ON THE UNDERSIDE OF SAID UPPER DRAWING BOARD, CONTROL MEANS MOUNTED ON SAID CARRIAGE MEANS, A LOWER MARKING ELEMENT ATTACHED TO A SECOND PORTION OF SAID CARRIAGE MEANS ADJACENT TO SAID LOWER DRAWING BOARD, SAID LOWER MARKING ELEMENT AND SAID INVERTED MARKING ELEMENT BEING RESPONSIVE TO MOVEMENTS OF SAID CONTROL MEANS FOR MARKING SAID SECOND AND UPPER DRAWING BOARDS, RESPECTIVELY, SAID CONTROL MEANS INCLUDING AN ARM PIVOTED ON SAID CARRIAGE MEANS, LOCKING MEANS RESPONSIVE TO THE EXTENT OF PIVOTING MOVEMENT OF SAID ARM FOR SELECTIVELY LOCKING SAID CARRIAGE MEANS TO SAID BEAM AND ALLOWING FREE TRANSLATION MOVEMENT OF SAID CARRIAGE MEANS ON SAID RECIPROCABLE MOVEMENT OF SAID CARRIAGE MEANS ON SAID BEAM AND LOCKING SAID BEAM TO SAID TRACK SO AS TO SELECTIVELY DRAW LINES ALONG A STRAIGHT PATH OR ANOTHER STRAIGHT PATH AT RIGHT ANGLES THERETO, WHEREBY A DRAFTSMAN CAN SIMULTANEOUSLY DRAW TWO SKETCHES RAPIDLY WITH EASE WHILE KEEPING THE DRAWING ON SAID UPPER DRAWING BOARD CLEAN AND UNSMUDGED. 